With the development of science and technology, performance of mobile phones is significantly improved and more and more images are stored in mobile phones. The images may come from various sources, such as photographs taken by a user through the mobile phone, webpage images, images generated by a social software, etc. With an increasing amount of images, a lot of memory space of the mobile phone may be occupied. How to reduce a memory usage of an image while maintain quality of the image is a technical problem to be solved.
Currently, cropping or compression is usually used to reduce memory space occupied by the image.
However, it may reduce clarity of the image when the image is displayed in a mobile phone with a high pixel density to crop the image with a unified height, for example 1024 pixels; while when a height of the image is less than the unified height, the image may be stretched and the clarity thereof may get worse; it may lose data and reduce the clarity of the image to compress the image with a unified size, for example 200 kb (kilobyte).